Growth of nanocrystalline MoO3 on Au(111) studied by in-situ STM
The growth of nanocrystalline MoO{sub 3} islands on Au(111) using physical vapor deposition of Mo has been studied by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). The growth conditions affect the shape and distribution of the MoO{sub 3} nanostructures, providing a means of preparing materials with different percentages of edge sites that may have different chemical and physical properties than atoms in the interior of the nanostructures. MoO{sub 3} islands were prepared by physical vapor deposition of Mo and subsequent oxidation by NO{sub 2}exposure at temperatures between 450 K and 600 K. They exhibit a crystalline structure with a c(4x2) periodicity relative to unreconstructed Au(111). While the atomic-scale structure is identical to that of MoO{sub 3} islands prepared by chemical vapor deposition, we demonstrate that the distribution of MoO{sub 3} islands on the Au(111) surface reflects the distribution of Mo clusters prior to oxidation although the growth of MoO{sub 3} involves long-range mass transport via volatile MoO{sub 3} precursor species. The island morphology is kinetically controlled at 450 K, whereas an equilibrium shape is approached at higher preparation temperatures or after prolonged annealing at the elevated temperature. Mo deposition at or above 525 K leads to the formation of a Mo-Au surface alloy as indicated by the observation of embedded MoO{sub 3} islands after oxidation by NO{sub 2}. Au vacancy islands, formed when Mo and Au dealloy to produce vacancies, are observed for these growth conditions.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15020077
- Report Number(s):
- UCRL-JRNL-203881; TRN: US200519%%161
- Journal Information:
- Journal of Chemical Physics B, Vol. 107, Issue 42
- Country of Publication:
- United States
- Language:
- English
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37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
ANNEALING
ATOMS
CHEMICAL VAPOR DEPOSITION
DEPOSITION
DISTRIBUTION
ELECTRON DIFFRACTION
MORPHOLOGY
NANOSTRUCTURES
OXIDATION
PERIODICITY
PHYSICAL PROPERTIES
PHYSICAL VAPOR DEPOSITION
PRECURSOR
SCANNING TUNNELING MICROSCOPY